Basket lining for centrifugals



Fein'. 13, v1934. E. ROBERTS l 1,946,500

` BASKET LINING FOR CENTRIFUGALS Filed Jan. 28. 1933 Patented Feb. 13,1934 UNITED STATES Pill'riezN'r.` oFFicE 1,946,500 BASKET IINING FOBCENTRIFUGAIS Eugene Roberts, Hastings, N. Y., assigner to The WesternStates Machine Company, Salt Lake City, Utah, a corporation of UtahApplication January 2s, 1933.k sex-inl No. 654,042 'z claims. (ci.21o-1s) of the material around the tcp and bottom edges' of the basketlining, thus producing imperfect and unsatisfactory centrifuging. It isthe object of the present invention toprovide an element of the filterstructure with a construction that shall eliminate this objectionableleakage and thus give full eil'iciency to the centrifugal separation 2oof liquid from the solid content, while in no way interfering with thecorrect positioning of the filter lining in the basket or with itseffectiveness inperforming its function of retaining the solid particlesor grains, while allowing free escape of the liquid.

Broadly speaking, the improvement comprises an open grid lining fordrainage, whose circumferential edge or edges are provided with a narrowthin strip of packing intimately united with the marginal portion of thelining member and projecting a slight distance beyond the edge of thelining member to form close contact with the adjacent rim of thecentrifugal basket. Ordinarily such a packing strip will be applied toboth the top and the bottom edge portions of the per- Fig. 1 is anelevation showing a perforated backing or lining grid, provided with theintegrally attached packing strips, affording drainage mpport for thenlter elements.

Fig. 2 is a cross sectional view on an enlargedo scale of a nlteringstructure arranged inside the centrifugal basket and containing thepresent improvement. 1 i

Flg.3isanedgeviewshowingthelapjointof thebridge member.

Flgad, 5 ando are detailviewsshowing the grid construction insection andin elevation. respectively. o

In the practice of my invention according to the form illustrated in thedrawing, the particular filter structure .comprises a spacing grid 1having 60 relatively large openings or interstices fitted against theinside of the perforated basket wall 10, which wall is provided at thetop with an annular rim 11 and at the bottom withan annular rim 12,which latter is secured in the usual mano5 ner to the customary openspider carried by the 'central supporting and driving shaft present inall centrifugals.

Inside the coarse wire mesh grid 1 is plac'ed a perforated lining sheetor backing 2, whose vertical width is slightly less than the verticaldistance between the top and bottom rims of the basket,-therebypermitting easy insertion ofthe perforated sheet or plate 2 withoutcausing buckling due-to the wedging of its top or bottom edge againstthe rigid subtending rims ofv the basket.

It is not commercially practicable to make parallel the edges of themesh forming the drainage gridfwhich spaces the filtering elements fromthe perforated basket wall, because of the distors0 tion of the wirefabric while it is being woven, but by providing the top and bottomedges of the wire grid with packing selvages 3 of material like softvulcanized rubber, it is possible to secure satisfactorily parallelismbetween the top and bottom edges of the -selvage portions of the ygridelement, so that the complete grid may be made of the' proper verticalwidth to permit the use of such a grid that will fit snugly between thetop and bottom rings of the centrifugal basket. Hence, a basketmeasuring 24 inches between the top and bottom rings may be tted with a24 inch wide grid lining, so that there is no possibility of leakage ofmaterial around the top or bottom edges of the lining which is a commonfault es with the lining constructions heretofore used. In practice, theopposite longitudinal, orwhat will be the circumferential edges of thegrid is placed in molds that embrace these two edges of the wire mesh orgrid member, in which a rubber composition is placed and the rubbercomposition is then vulcanized to a moderate degree,the mold beingdimensioned to form the rubber selvages of substantially the samethickness as the thickness of the woven mesh and projecting outwardbeyond the ragged edges of the mesh to form edge portions that are inparallelism with each other.

To facilitate the forming of a smooth joint between the lapped endsofthe grid. several vertical orcross wires are withdrawn from 4the op-11o in Fig. 1, and the end portions of the rubber selvage or border arebevelled to a thin edge, so that when overlapped they will be of thesame 5 thickness as other portions of the selvage, as shown at 3P- inFig. 3. 'Ihis is practicablel because there is no substantial stretch tothis coarse wire mesh member after it is properly fitted into thebasket. The projecting ends le of the circumferential wires, from `whichthe coarse wires have been stripped as above explained, will lap by eachother in side by side relation, as shown in Fig. 2, so as to afford -anintermediate support for the interior filter elements which restagainstthe grid and which are held. by it in spaced relation from the basket inorder to afford adequate drainage passages to the relatively largeperforations in the basket wall.

The filter elementsmay be of anysuitable construction and in this caseare shown as comprising an intermediate bridge or supporting plate 2provided with relatively coarse perforations and against the inner faceof this bridge plate is mounted a finer wire mesh backing 7 forming aspacing support for the finely perforated sheet metal lining 6. Thisconstruction is similar to that shown in'my earlier patent No.1,581,089. Since the perforated bridge plate 2 has its top and bottomedge portions resting directly against the compressible rubber selvages3, which may be 1/2 inch more or less in widthyit is not necessary tohave the bridge plate or the other filter elements 6 and 'I nt snuglyinside the top ring 11 and the bottom ring 12 of the basket, and yetleakage of material around the top and bottom edges of the lter liningsis completely eliminated. While it is preferred that the basket wall 10shall have its top and bottom rows of perforations spaced a substantialdistance from the adjacent top and bottom rings of the basket in orderto afford a smooth continuous support for the selvage edges of thelining or grid, nevertheless such an arrangement is not essential.

In Figs. 5 and 6 is shown a slightly modied form of joint for thespacing grid, in which the projecting ends 1b of the circumferentialwires, from which the crossed wires have been stripped, are bevelled toa thin edge or point and are overlapped upon the adjacent portion of thewire mesh containing the cross Wires. In this case a somewhat longerbevel is given to the overlapping end portions of the selvages 3 so asto avoid any substantial increase in thickness at the lapped joint. Y

By means f the above described construction .it is possible not only topractically eliminate the wasteful leakage of material around the edgesof the lter linings, but the advantage is also secured of facilitatingthe insertion of the lter 50 elements themselves because they may be cutsomewhat narrower than the inside vertical width of thebasket, since thepacking selvages or borders on one of the lining elements nt snugly'inside the top and bottom members of the basket.` Heretofore it hasbeen the practice to make centrifugaly baskets with the top row ofoutlet holes close up to the top rim of the basket, but I have shown inFig. l2 the top row of holes located some distance below the inside ofthe top 70 rim 11 to afford a somewhat unbroken surface 'for the selvageportion .of the backing grid and `I have followed the same practice atthe bottom of the basket by leaving blank the bottom area of the basketwall for a short distance to form a similar support for the selvage 3 ofthe backing' posite end portions of the wire mesh, as shownI grid. Thisarrangement affords a smooth, even disposition of the selvage edgesperfectly sealing the basket against the escape of liquid around thebottom or around the top edges of the filter linings.

What I claim is:

1. A foraminous filter supporting grid element for a centrifugal baskethaving relatively large openings for the passage of liquid, the upperand lower edge portions of said grid being provided withcircumferentially extending selvage strips of yielding material adaptedto form sealing con tact with the inside face of the basket adjacent tothe top and bottom members thereof to pro'- vide a drainage support foran interiorly disposed iiltering element, while preventing leak-Y age ofthe material being treated around the edges of the filtering element.

2. A grid l.backing for the ltering elementof a centrifugal basketcomprising a course wire mesh grid adapted to be fitted inside thebasket to afford drainage support for the ltering structure and havingits top and bottom edge portions included within top and bottom selvagestrips of vulcanized rubber adapted to form sealing contact with theadjacent surface of the basket to prevent leakage of Ithe material beingtreated around the top and' bottom edges of the filter structure.

3. A supporting drainage grid for a lter comprising a coarse wire meshfabric having its top and bottom edge portions imbedded in top andbottom selvage strips of vulcanized rubber projecting somewhatI beyondthe wire mesh to form top and bottom parallel packing strips adapted 110to lie in close contact with adjacent surfaces of the basket to providesealing joints against the escape of material being treated around theedges of the ltering structure.

4. A spacing and supporting grid for the filter 115 element of acentrifugal basket embracing in its construction, a coarse wire meshhaving its top and bottom edges imbedded in parallel strips ofvulcanized rubber substantially equal in thickness .to the thickness ofthe wire mesh grid and having their outer portions extending somewhatbeyond the wire mesh to form compressible parallel seal- -ing edges attop and bottom of the grid.

5. A grid lining element for a centrifugal basket embracing in itsconstruction, a relatively 125 coarse wire mesh fabric having its topand bottom edges imbedded in parallel selvage strips of vulcanizedrubber substantially equal in thickness to the thickness of the wiremesh, the end portions of said selvage strips being bevelled to arthinedge to form, when the grid is inserted in the basket, a lapped joint/ofa thickness substantially equal to other portions of the selvage.

6. A grid lining element for a centrifugal basket embracing in itsconstruction, a relatively coarse wire mesh fabric having its top andbot-4 ,tom edges imbedded in parallel selvage strips of vulcanizedrubber substantially equal in thickness to the thickness ofthe wiremesh, the end portions of said selvage strips being bevelled to a thinedge to form, when the grid is inserted ln the basket, a lapped joint ofa thickness substanv tially v:equal vto other portions of the selvage,the vertical wires of the mesh at the 'overlapped ends of the grid beingremoved to permit the end por- 145 l tions of the circumferential wiresto lap by each other in side by side relation to form support for thefilter element at the 'overlapping joint.

,7. The combination with a centrifugal basket for the extraction ofliquid comprising a perlpheral perforated basket wall and top and bottomrings secured thereto,

Said rings being spaced a substantial distance from the next row otperforations in the peripheral unbroken surface for the ing elements,and a. iilter at top and bottom with a wall to afford a smooth supportof the lter 1inlining element provided selvage oi' packing mathe lining.

` EUGENE ROBERTS.'

terial adapted t0

